The Vancouver police officer who shot and killed a bipolar man armed with a bicycle chain did not use excessive force, B.C.'s police complaint commissioner has ruled.

Const. Lee Chipperfield fired nine shots at Paul Glenn Boyd in a span of 80 seconds on Aug. 13, 2007 during a confrontation on Granville Street. Eight of those shots hit Boyd, and the final bullet to the head was fatal.

The Criminal Justice Branch decided in 2009 not to lay charges against Chipperfield, and on Monday police complaint commissioner Stan Lowe announced that his office will not take any further action against the constable.

"There does not exist clear, convincing and cogent evidence that establishes on a balance of probabilities that Constable Chipperfield used unnecessary or excessive force during this incident," Lowe wrote in his decision.

He acknowledged, however, that there were major discrepancies between different witness accounts that made it difficult to figure out exactly what happened.

"In particular, there exists a contentious issue surrounding the level of threat posed by Mr. Boyd at the time that the last and intended fatal shot was fired," Lowe wrote.

Boyd, 39, was manic and wasn't taking his medication on the night he was killed, his psychiatrist told a 2010 coroner's inquest.

Four officers responded to 911 calls about a possible assault on the night of the shooting, and found Boyd kneeling on the ground at a bus stop, clutching a hammer in his hand, according to Lowe's decision. When one of the constables tried to handcuff him, Boyd grabbed a bike chain and struck the officer in the head, knocking him to the ground and leaving a cut that would require stitches.

Boyd smacked another officer in the back with the chain before running into the middle of the street, still swinging the chain. The constables said that when they tried to approach him, Boyd began aggressively walking toward them.

Chipperfield has said he thought he had run out of options for pacifying the angry man, and he feared Boyd was going to attack him or someone else.

He began firing his gun, but at first none of the shots appeared to have any effect and Boyd kept walking toward him. Some witnesses said they believed that Boyd must have been wearing body armour or that Chipperfield was firing rubber bullets.

One of the other officers on the scene maintains that he had time to run in and grab the chain from Boyd before the last and fatal shot was fired, but Chipperfield has said he wasn't aware of that and would have stopped shooting if he knew the other man was disarmed.

A psychologist who reviewed the incident found that the intense emotion of the confrontation left Chipperfield blind to everything happening around him and the officer was "shooting to save his life rather than being focused on shooting to stop Mr. Boyd."

Civil liberties watchdog questions conclusion

The BC Civil Liberties Association issued a statement Monday asking why the police complaint commissioner took nearly five years to complete his investigation into Boyd's death.

"A five-year wait for this? The only result of this five-year-long investigation is ever more tortured explanations for an officer's actions in shooting a disarmed and badly injured man in the head," BCCLA director David Eby said in a release.

Eby added that he hopes that B.C.'s new civilian-led Independent Investigations Office will do a more satisfactory job of looking into police shootings.

"We expect some level of accountability for officers shooting every bullet in their handguns beyond an expert saying, literally, that this officer was in a blind panic, which apparently immunizes the officer from legal or procedural review," he said.

A police disciplinary authority has also found there was insufficient evidence to discipline Chipperfield for his actions. The coroner's jury that reviewed Boyd's death recommended that all officers be provided with intermediate weapons like bean-bag guns and Tasers to deal with distraught people.